The researchers sampled 2,550 bottled water users, the first study to do so on a national level. Respondents reported recycling an average of six out of every 10 plastic water bottles, considerably more than the government’s estimate of a 24 percent recycling rate—or just two or three bottles for every 10 used. The researchers also found that bottled water drinkers tend to be affluent, disproportionately female, and middle-aged. They spend an average of $12 a month on bottled water.

People who don’t recycle at all and those from lower income groups are more likely to start recycling plastic water bottles when laws and other incentives are put in place, according to lead author W. Kip Viscusi, University Distinguished Professor of Law, Economics, and Management at Vanderbilt University.

The researchers examined who is more likely to recycle and whether recycling laws and bottle return programs boost recycling efforts. The waste associated with plastic water bottles has become a prominent national issue with more than two million tons of bottles containing PET, or polyethylene terephthalate, ending up in landfills every year.

The researchers sampled 2,550 bottled water users, the first study to do so on a national level. Respondents reported recycling an average of six out of every 10 plastic water bottles, considerably more than the government’s estimate of a 24 percent recycling rate—or just two or three bottles for every 10 used.

The researchers also found that bottled water drinkers tend to be affluent, disproportionately female, and middle-aged. They spend an average of $12 a month on bottled water.

They also found that nearly 30 percent of those surveyed do not recycle plastic water bottles at all while around 40 percent say they recycle every water bottle they use. The next largest group was those who report recycling eight or nine bottles for every 10 they use.

It is not good enough for states to have recycling goals. The researchers found that recycling laws and incentives for recycling, such as deposit returns, are more effective in changing non-recyclers into committed recyclers.

The average number of bottles out of 10 that are recycled rises from 4.38 in states with no effective recycling law and no water bottle deposit law to 6.10 if the state has an effective recycling law and 8.34 if the state also has a water bottle deposit law.

Strong recycling laws and water bottle deposits are effective in transforming people from non-recyclers to diligent recyclers.

“Bottle deposits work because they provide a financial reward for recycling,” Viscusi says. “Having a recycling law in the state only makes a difference if it promotes recycling by fostering curbside pickup or providing for convenient recycling centers. Mandatory recycling is also effective, but simply declaring that the state has a goal doesn’t work. Effective recycling laws must go beyond symbolic gestures.”

“What was really surprising is that recycling laws and bottle deposits have a dramatic impact when they are effective. A person who formerly recycled zero to two bottles out of 10 will jump to recycling 8 to 10 bottles out of 10 when these policies take effect,” Viscusi adds.

Researchers from Vanderbilt and Duke University contributed to the study, which was supported by a grant from the U.S. Environmental Protection Agency.